It is planned to produce hybridoma lines producing monoclonal antibodies to four gonococcal surface antigens of great importance in pathogenesis. The reactivity of a number of antibodies to pili will be related to the primary structure of this protein, and the ability to inhibit adhesive properties will be determined in order to locate the receptor site within the pilin molecule. Similarly, the determinants seen by monoclonal antibodies to proteins I will be correlated with the primary sequence, and their ability to mediate opsonization, complement dependent bacteriolysis and translocation to eukaryotic membranes. Antibodies will be developed to protein III, a constant antigen present in all gonococci, and their capacity to opsonize and to promote or block bacteriolysis determined. Lastly, antibodies to IgA proteases will be developed, with the particular intent to find clones inactivating the enzyme. Once these are available they will be used to determine if it is possible to identify the active site by immunochemical techniques. The goal is to design an immunizing agent favoring the production of inactivating antibodies.